Within the discussion of homeostasis, virtually all authors ignore the importance of biological rhythms (circadian or otherwise).
Our own text's author (Martini) only makes a passing reference to it in the special senses chapter(chapter 17,far removed from the chapter 1 discussion of homeostasis):
"This circadian rhythm affects your metabolic rate,endocrine function, blood pressure, digestive activities, awake-sleep cycle, and other physiological and behavioral processes".

Well, is everything that's important actually foundational? Can we meaningfully discuss circadian rhythms of body temperature without some prior understanding of where heat comes from in the body and how heat is retained and lost? Which is more foundational the circadian rhythm portion or the basic metabolism portion? Or do they stand alone and, although overlapping, are totally independent of one another? What do you think?